After oral administration, valacyclovir, the L-valyl ester of acyclovir, converts to the antiherpes virus drug, acyclovir. The bioavailability of acyclovir after valacyclovir administration is between 3- to 4.5-fold higher than that achieved after oral acyclovir administration. Therefore, despite the drug's short terminal half-life (3 hours), acyclovir plasma concentrations obtained after oral administration of the prodrug offer a more convenient dosage regimen in patients with herpes zoster than that required after acyclovir administration. Acyclovir is also used for viral infection prophylaxis in patients with hematologic disorders and in those who have undergone solid organ transplantation. We have described a simple and selective liquid chromatographic method for the determination of acyclovir in plasma using a new polymeric reversed-phase sorbent for solid-phase extraction. A mean acyclovir absolute recovery of 90% was found after elution of the drug from the cartridge with the mobile phase. This procedure allowed us to measure 62.5 ng/mL of acyclovir with an acceptable precision using a plasma volume of 250 microL, and no drug was found to interfere with the assay. This method is suitable for the therapeutic monitoring of acyclovir in patients who have been given a wide variety of coadministered drugs.
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http://dx.doi.org/10.1097/00007691-199902000-00020 | DOI Listing |
Clin Microbiol Infect
December 2024
Institute of Medical Microbiology and Virology, University Medical Center, Göttingen, Germany.
Background: Despite established antiviral therapy for herpes simplex virus, varicella zoster and cytomegalovirus encephalitis, the outcome remains poor.
Objectives: To assess pharmacokinetic (PK) and pharmacodynamic (PD) data of antiviral drugs in the central nervous system (CNS) to optimize the treatment of Herpesviridae encephalitis.
Sources: PUBMED search 1950 to September 2024, terms (1) "encephalitis" and ("HSV" or "VZV" or "CMV") or (2) cerebrospinal and ("(val)acyclovir" or "(val)ganciclovir" or "foscarnet" or "cidofovir").
Eur J Case Rep Intern Med
October 2024
Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, Groningen, The Netherlands.
Background: Valacyclovir-induced neurotoxicity is a rare side effect. The aim of this study was to perform a retrospective analysis of patients with valacyclovir-induced neurotoxicity and establish valacyclovir plasma concentrations in a tertiary hospital between January 2018 and November 2022.
Case Descriptions: In total 208 patients were identified with measured acyclovir concentrations, and the electronic health records of these patients were analysed.
J Med Virol
October 2024
Department of Pulmonology, Faculty of Medicine, Uludağ University, Bursa, Turkey.
Respir Med Case Rep
September 2024
Division of Pulmonary, Critical Care, Sleep and Occupational Medicine, USA.
Central airway obstruction (CAO) is generally defined as airflow limitation due to >50 % occlusion and is most commonly due to malignant etiologies. However, benign etiologies, including herpes-simplex-virus (HSV) endobronchial pseudotumor, can occur. Due to the rarity of HSV causing airway obstruction, an evidence-based approach to the bronchoscopic resection and standardization of therapy after removal are lacking.
View Article and Find Full Text PDFFront Med (Lausanne)
August 2024
Department of Intensive Care Unit, Fifth Affiliated Hospital of Wenzhou Medical University, Lishui Municipal Central Hospital, Lishui, China.
This case report details the clinical course of a 16-year-old female student with infection complicated by autoimmune encephalitis, spanning from 6 February 2022, to 12 April 2022, with a one-year follow-up. The patient presented with a two-week history of cough and fever, followed by altered consciousness and neuropsychiatric symptoms, including hyperactivity and incoherent speech. Despite normal brain MRI findings, cerebrospinal fluid (CSF) analysis confirmed with titers of, and positive IgLON5 antibodies.
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